U.S. Pat. No. 6,138,596, which is incorporated herein by reference, discloses a hydraulic damper for a steering system, such as that of a boat or watercraft. A manually movable steering mechanism, such as a steering wheel, is connected to a piston and cylinder combination in such a way that rotation of the steering wheel causes relative movement between the piston and cylinder. Hydraulic fluid is disposed within the cylinder in such a way that movement between the cylinder and piston requires the hydraulic fluid to move from one portion of the cylinder to another portion of the cylinder. This fluid movement is conducted through a conduit which can be external to the cylinder or internal to the cylinder and extending through the piston.
U.S. Pat. No. 6,273,771, which is incorporated herein by reference, discloses a control system for a marine vessel incorporating a marine propulsion system that can be attached to a marine vessel and connected in signal communication with a serial communication bus and a controller. A plurality of input devices and output devices are also connected in signal communication with the communication bus and a bus access manager, such as a CAN Kingdom network, is connected in signal communication with the controller to regulate the incorporation of additional devices to the plurality of devices in signal communication with the bus whereby the controller is connected in signal communication with each of the plurality of devices on the communication bus. The input and output devices can each transmit messages to the serial communication bus for receipt by other devices.
U.S. Pat. No. 7,699,674, which is incorporated herein by reference, discloses a steering mechanism that connects the shaft of an actuator with a piston rod of a hydraulic cylinder and provides a spool valve in which the spool valve housing is attached to the hydraulic cylinder and the shaft of the actuator extends through a cylindrical opening in a spool of the spool valve. The connector is connectable to a steering arm of a marine propulsion device and the spool valve housing is connectable to a transom of a marine vessel.
U.S. Pat. No. 8,046,122, which is incorporated herein by reference, discloses a control system for a hydraulic steering cylinder utilizing a supply valve and a drain valve. The supply valve is configured to supply pressurized hydraulic fluid from a pump to either of two cavities defined by the position of a piston within the hydraulic cylinder. A drain valve is configured to control the flow of hydraulic fluid away from the cavities within the hydraulic cylinder. The supply valve and the drain valve are both proportional valves in a preferred embodiment of the present invention in order to allow accurate and controlled movement of a steering device in response to movement of a steering wheel of a marine vessel.
U.S. Pat. No. 8,113,892, which is incorporated herein by reference, discloses a marine propulsion control system that receives manually input signals from a steering wheel or trim switches and provides the signals to first, second, and third controllers. The controllers cause first, second, and third actuators to move control devices. The actuators can be hydraulic steering actuators or trim plate actuators. Only one of the plurality of controllers requires connection directly to a sensor or switch that provides a position signal because the controllers transmit signals among themselves. These arrangements allow the various positions of the actuated components to vary from one device to the other as a result of calculated positions based on a single signal provided to one of the controllers.